Process of preparing 1-amino-10-anthrones and the products obtainable thereby



Patented July 25, 1933 UNITED STATES T GEORG KRKNZLEIN AND WALTER BROEKEIR, or FRANRFORT-QN Ti E-MAIMHOG ST,

AND ARTHUR woLrRAM, or'FRANKFORT-o1\T-THE-MAI1\ RoDEL RI1vr,"GERMANY;

Ks, me, or NEwYoRK, -Y., ACORIPORAQ ASSIGNORS' To, GENERAL ANILINE wo ron or DELAWARE PROCESS or PREPARING I-AMINOI-IO-ANTHRONES Am) THE V TI-IEBEBY i 'PRO UC s-LoisTA NARLR No Drawing. Application filed July '8, 1932, Serial No. 621,518, and in Germany Ju1y17, 1931.w

The present invention relates to a new process of preparing l-amino-lO-anthrones and to the'products obtainable thereby.

We have found that l-amino-lO-anthrones are. obtainable in an easy manner and with a very good yield by acting with an acid condensing agent on a compound of the following general structure into the cor-respondinganthraquinones when their alkaline solution is exposed to air or treated with an oxidizing agent.

It is surprising that the above described reaction occurs in such a smooth manner and with a very good yield of l-amino-lO-anthrones since the 2' amino-2-benzoylbenzoic acid condenses extremely difliculty and only under special conditions with formation of l-alninoanthraquinone- The easy course of the reaction is, furthermore, surprising in view of the fact that the ring closure must take place in meta-position to the amino group, ie in a position which in comparison to the orthoand para-posltlon is known to be difliculty accessible to reaction.

The products obtainable according to the present process are new, for

of the following formula;

v H2 NHi wherein X stands for hydrogen or alkyl. I

I The following examples serve ;to illustrate the invention, but they are not intended instance, those to limit it thereto, the parts being by. Weight: 5

(1) 80 parts of 2-aminQ-2benzylbenzoic acid are dissolved in 800'parts of sulfuric acid (96%) and heated for aquarter ,of an hour at about 60 C. toabout 659C. The "reaction xmixture; is then poured ,into ice-water. The yellow-green precipitate'obtain'ed is filtered with suction and washed until neutral. After recrystallization from ort'ho dichlorobenzene or xylene ;or chlorobenzene, the l-ainino-10anthrone forms fine needles meltingi at 172 C. to 173C. The

product dissolves in concentrated sulfuric V acid to a light yellowsolution showing a weakly green fluorescence. In caustic soda solution it dissolves to a' yellow: solution. 1'

On exposure to air or on additionpf' an oxldlzing agent, there separates from. 1ts

alkaline-solution alpha-aminoanthraquinone.

(2) 125parts' of the sodium salt. ofv 2':

amino-2-benzylbenzoic acid; are introduced a into 1500 parts of sulfuric acid (90%) at about C. to about C. After the 7 whole has been dissolved, it is heated for half an hour at about". C. The product is worked up as indicated in "Example 1.

amino-2-ben'zylbenzoic acid are introduced "in small portions-into 2000 parts of sulfuric acid (88% As soon as hydrochloric acid isno longer precipitated and the whole {has J90 132 parts of the hydrochloride of 2' acid monohydrate and the whole is heated for limin utes-at about 15 Cato about 50 C. The condensation product is obtained I as described'in Example 1.

acid are introdiice'd in portions into 4410' parts of' chlorosulfonic "acid, while cool-111g to about0 G. to about 10 (3., dissolved and the whole is stirred for 10 minutes atroom temperature. After decomposition of the melt by means of ice, the l-amino-lO- anthrone-yis obtained as described in Example 1. I v

(6) Into a inelt of 365 parts ofaluniiniuin chloride and 75 partsv of sodium chloride there areintroduced at. about 120 0., 55 parts of 2-amlno-2ebenzylbenzo1c acid.

The whole is molten for half an hour at about 120 0., to about 125 (1, and then decomposed with ice-water. brown product which'has separated, is filtered with suction extracted with boiling dilute hydrochloric acid in order to remove the aluminium salts and washer'l until neutral. It is further purified asindicated in'EX'ample 1.

80 parts of 2-amino--inethyl+2- benz'ylbenzoic acid are dissolved in 800' parts of-sulfuricacid (96%) and heated for 15 minutes at about C. to about C. The reaction productis poured into icewater, theyelloW-green precipitate is filtered with suction and washeduntil neutral. 1'-aniin'o-3-metl1yl-10-anthr0ne I crystallizes from chlorobenzene inthe formof yellowbrown needles'lnelting at'1 96 C. to 197 C. Itdissolves in concentrated sulfuric acid to alight yellow solution showing a weakly green fluorescence and in caustic soda solution to a yellow solution. On exposure to air or onaddition of hydrogen superoxlde,

' there separates from itsalkaline solution 1 -a nino-3-niethyl-anthraquinone melting at 193 C;

Ve claim 1 1. The process which comprises causing an acid condensing agent to react With a :compound of the general structure 3;The process which comprises causing an acid condenslng agent to react with 2'- amino-4-n1ethyl-2-benZylbenZoic acid.

The yellow- 4. The process which comprises heating i'or about a quarter of an hour at a temperature otabout5 C. toabout C. a compound of the general structure 2 1 7 p I I V H being unsubstituted in position X, which is dissolved in concentrated sulfurlc ac d 1 so The process which comprises heating for about a quarter of anhour at a temperature of about45 C, toabout 65 :C. 2"- aniino-2-benzylbenzoic acid which is dissolved in concei itratedsulfuric acid.- p 0 6. The process which comprises heating for about a;quarter-ofgan hour ata temperatur'e: of aboute5 C." to about 65 0.: 2' aininoA-methyl-2 benzylbenzoic acid which dissolved in concentrated sulfuric acid.

7 The process which comprises heating for about a quarter of an hour at a temperature of about 45 C. to about 50 C. a compound of the general structure:

being unsubstituterl in position X, which is dissolved in sulfuric acid monohydrate.

' 8 The .process which comprises heating for abouta quarter of'an hour at a'teinperature of about 15 C. to about 50 C. 2- 'amino-2-benzylben zoic acid which is dis solved in sulfuric acid inonohydrate. -9;- The process which comprises heating forabout a quarter ofan hour art-a temperatureof about 15 to about 50 0. 2- amino 4:-methyl-2-benzylbenzoic acidwliioh is dissolved in sulfurio'acid lnonohydrate.

'10. The process 'which comprises'heating for about a-quarter'o f an'hour at a temperature of about 15 C; tofabout 50 C. iii-com pound of the-general structure: v

l -F being unsubstituted-in position X, which is dissolved in sulfuric acid monohydrate' and treating the anthrone compound thus 'obtainablei in an alkaline solution withjan oxidizing: agent. 1'30 11. The process which comprisesheating for about a quarter of an hour at a temperature ofvabout 45 C. to about 50 C. 2-

amino-2-benzylbenzoic acid Which is disi.

solved in sulfuric acid inonohydrate and treating the anthrone compound thus 0btainable in an alkaline solution with an oxidizing agent. I

12. The process which comprises heating for abouta quarter of an hour at a temperature ofabout 45 C. to about 50 C. 2'- amino-l-methyl-2-benzylbenzoic acid Which is dissolved in sulfuric acid monohydrate and treating the anthrone compound thus obtainable in an alkaline solutlon \vlthan oxidizing agent.

13. The compounds of the'following general structure wherein X stands for hydrogen or alkyl, I

forming on exposure to air or addition of an oxidizing agent the." correspondmg anthra.-. v

quinone compounds,

14. l-amino-lO-anthrone forming needles, inelting at 172 C. to 173 (1, dislight yellow solution showing a Weakly green fluorescence and'in ca-usticsoda solution to a-yellow solution and, being transformed into the corresponding anthraquinone When its alkaline solution is exposed to air or treated With an oxidizing agent. 7 l

. 15; 1-an1ino-3-1nethyl-1O-anthrone5 crystallizing from chlorobenzene in the form of yellow-brown needles, melting at l96- C. to

197 0., dissolving in'concentrated sulfuric acid to a light yellow solution showing a weakly green fluorescence and in caustic soda solution to a yellow solutionand being transformed into the corresponding anthraquinone when its alkaline solution is exposed to air or treated superoxide; I V GEORG :KRANZLEIN.

ARTHUR WOLFRAM;

with hydrogen :WALTER BROEKER. 

